I know this question is odd, but unfortunately we have a lot of unhoused addicted people in my city. I often see them sitting on a bench bent at the waist in half like a rag doll, or standing somewhere half bent over, like stooped over nodding out I guess? I don't really know anything about substance use, but it's such a strange sight, what substances cause them to bend over like this?

Poor souls. The mayors of big cities here have asked the provincial government to declare a state of emergency due to homelessness and addiction being so rampant, but Doug Ford doesn't give a shit about them.